A UDN (Ultra-Dense Network, ultra-dense network) is a network with high station density, a large quantity of stations, and a short inter-station distance. A station address of a base station in the UDN network is generally selected on a facility that is convenient for construction, such as a light pole or an outer wall of a building along a street, and coverage and a capacity of the base station can be flexibly provided. However, this address selection manner is not conducive to configuration of a high-power power supply and fiber backhaul. In addition, there is a large quantity of micro base stations, and there is a plug-and-play usage manner. Therefore, factors such as networking costs and networking flexibility are comprehensively considered, and wired backhaul cannot be configured for each micro base station.
In a current UDN network, some base stations have high-performance wired backhaul. These base stations are macro base stations and can be used as gateways to help a wireless backhaul micro base station to backhaul data. To enlarge a coverage area of a cell, an MR (Mobile Relay, mobile relay) is used between the macro base station and the micro base station. When accessing a network, the MR needs to select an upstream node of the MR, and the upstream node is the macro base station or the MR that has accessed the network. A method for selecting the upstream node is that the macro base station and the accessed MR broadcast a DCD (Downlink Channel Descriptor, downlink channel descriptor) message, where the DCD message includes a hop count between the accessed MR and the macro base station; and a to-be-accessed MR receives the DCD message, and selects a proper accessed MR or a macro base station as the upstream node according to the hop count between each accessed MR and the macro base station and a channel capacity between a to-be-accessed base station and each accessed MR.
However, the to-be-accessed MR uses only the hop count between the accessed MR and the macro base station and the channel capacity between the to-be-accessed base station and each accessed MR, and because the hop count between the accessed MR and the macro base station and the channel capacity between the to-be-accessed base station and each accessed MR cannot represent a real backhaul capability of the accessed MR, a case in which a selected upstream MR cannot meet a backhaul requirement for the to-be-accessed MR may occur.